Modified water-soluble polyacrylamides and method of making same



United States Patent ODIFIED WATER-SOLUBLE POLYACRYLAM- IDES ANDIVIETHOD OF MAKING SAME Fred E. Boettuer, Philadelphia, Pa., and WarrenD. Niederhauser, Huntsville, Ala., assignors to Rohm & Haas Company,Philadelphia, Pa., a corporation of Delaware No Drawing. ApplicationFebruary 14, 1957 Serial No. 640,069

17 Claims. (Cl. 260-861) This invention deals with modifiedwater-soluble polyacrylamides as new compositions of matter. It furtherdeals with methods for the preparation of these modified water-solublepolyacrylamides.

The modified water-soluble polyacrylamides contemplated in thisinvention may be represented by the following formulae:

in which X and Y are integers, M is a cation, and D is a modifyingmonomeric unit capable of copolymerization with methyl acrylate, to bemore fully explained hereinafter.

The compounds of this invention corresponding to Formulas I and II areprepared by reacting N-methylglucamine with a modified poly(methylacrylate) in molecular ratios in the range of from about 0.1 to 1.1equivalents of methyl acrylate, with Formula I representing thecompounds exhibiting a 1:1 ratio of stated units and Formula IIrepresenting the other ratios. The modified po1y(methyl acrylates) areto be construed to mean in the preferred embodiment any methyl acrylatesthat can be copolymerized with any alkyl methacrylates in which thealkyl portion contains from one to eighteen carbon atoms or any alkylacrylates in which the alkyl portion contains from two to eighteencarbon atoms. It is also quite possible and satisfactory to modify thepoly(methyl acrylates) with any other compound that readily forms acopolymer with methyl acrylate. The compounds that may be employed tomodify the poly(methyl acrylates) include acrylonitrile, acrylic acid,styrene and ring-substituted styrenes containing no more than a total of18 carbon atoms, hydroxysubstituted alkyl vinyl ethers in which one totwo hydroxy groups may be attached to an alkylene chain of two toeighteen carbon atoms and in which no hydroxy group is closer to theether oxygen than two carbon atoms, and in which, if there are twohydroxy groups, such groups are on different carbon atoms;alkanamidoalkyl vinyl ethers in which the non-vinyl portion containsfrom 3 to 23 carbon atoms; vinyl alkyl sulfides in which the alkylportion contains no more than 18 carbon atoms and in which portion theremay be one or two hydroxy substituents provided no hydroxy substituentis nearer to the sulfur atom than two carbons and if two P we hydroxysubstituents are present they are on different carbon atoms;dialkylaminoalkyl vinyl sulfides in which the dialkyl portion attachedto the amino nitrogen considered individually may contain up to abouteight carbon atoms and considered collectively may form a fivetosix-membered heterocyclic amino group with the amino nitrogen atom, andin which the nitrogen atom is always tertiary and is connected to thesulfur atom by means of an alkylene group containing from two toeighteen carbon atoms; N-vinyl lactams and alkyl substituted N-vinyllactams preferably containing from six to twenty carbon atoms; alkylvinyl sulfones in which the alkyl portion contains up to about eighteencarbon atoms; N-vinylalkyleneureas containing from five to twelve carbonatoms; and N vinyl N aminoalkylalkyleneureas containing from seven totwenty carbon atoms. In the above monomers, the alkyl groups may exhibitany possible spatial configurations such as normal, iso, or tertiary.These alkyl groups may be acyclic or cyclic, including alkyl substitutedcyclic, as long as the total carbon content conforms to the definedamount. In the hydroxy substituted compounds the hydroxy group or groupsmay be attached at any possible location as long as the previousdefinition is adhered to. In the ring substituted styrenes thesubstituents may occupy any possible ring location or locations and whenthe substituents are alkyl groups they may have any possible spatialconfiguration.

Typical of the monomer reactants that may be employed to modify thepoly(methyl acrylates) include preferably ethyl acrylate, isopropylacrylate, cyclopentyl acrylate, Z-ethylhexyl acrylate, decyl acrylate,dodecyl acrylate, octadecyl acrylate, methyl methacrylate, tertbutylmethacrylate, eyclohexyl methacrylate, octyl methacrylate, undecylmethacrylate, and octadecyl methacrylate. There may also be typicallyused acrylonitrile, acrylic acid, styrene, p-butylstyrene,p-octylstyrene, ochlorostyrene, o,p-dipropylstyrene,o-methyl-p-decylstyrene, hydroxyethyl vinyl ether, hydroxyoctyl vinylether, dihydroxydodecyl vinyl ether, formamidoethyl vinyl ether,butanamidodecyl vinyl ether, acetamidooctadecyl vinyl ether, butyl vinylsulfide, hydroxybutyl vinyl sulfide, octyl vinyl sulfide, octadecylvinyl sulfide, dimethylaminoethyl vinyl sulfide, diethylaminodecyl vinylsulfide, morpholinopentyl vinyl sulfide, pyrrolidinyloctyl vinylsulfide, piperidinodecyl vinyl sulfide, N-vinyI-2-pyrrolidone,Nvinyl-5-rnethyl-2-pyrrolidone, N-vinyl-4,4-diethyl-Z-pyrrolidone,N-vinyl-4-butyl-5-octyl-2-pyrrolidone, N-vinyl-6-methyl-2-piperidone,N-vinyl-6-octyl-2-piperidone, N-vinyl-2,2,6,6-tetramethyl-4-piperidone,N-vinyl- 2-oxohexarnethylenimine, N-vinyl-5,5-dimethyl 2oxohexamethylenimine, N-vinyl 4-butyl-5-octyl-2-oxohexamethylenimine,methyl vinyl sulfone, isobutyl vinyl sulfone, tert-octyl vinyl sulfone,dodecyl vinyl sulfone, octadecyl vinyl sulfone, N-vinylethyleneurea,N-vinyltrimethyleneurea, N-vinyl-1,2-propyleneurea, N-vinylbutyleneurea,N-vinyl-N'-aminoethylethyleneurea, and N-vinyl-N-dibutylaminododecylethyleneurea. The symbol D is to be construedto mean any of the monomeric units that copolymerize with methylacrylate. For instance, methyl methacrylate, as represented by D, wouldbe r C-CHrand oetyl acrylate would be -CI'I-CH1 COOCH; C00C8 l7 Theother methyl acrylate modifying monomeric units would haverepresentations as D according to the above explanation.

The range of proportions of the methyl acrylate unit to the modifyingmonomer unit which is represented as D in the above given formula mayvary within the range of about 1:1 to 12:1, as desired.

While the present reaction between N-methylglucamine and the modifiedpolymeric methyl acrylates will occur only at the methyl acrylateportion of the copolymer, as indicated in Formulas I, II, and III, it ispossible to obtain valuable products wherein N-methylglucamine isreacted with a methyl acrylate unit that has been modified by any of themodifying monomers presented heretofore. In this way it is possible toobtain modified water-soluble polyacrylamides that may have propertiesthat vary as the modifying monomeric unit varies in kind and amount. Forinstance, it is possible to obtain a modified water-solublepolyacrylamide that may on drying out have enhanced stiffeningcharacteristics not possible with unmodified water-solublepolyacrylamides. Also, it is similarly possible to incorporate otherdesirable properties, such as enhanced toughness, hardness, chemicalresisting, water insensitivity and others, by employing a modifiedpolymeric methyl acrylate in a way not known heretofore. It is thereforepossible by the method of this invention to provide modifiedwater-soluble polyacrylamides that have a variety of characteristics notpreviously achievable with the unmodified water-soluble polyacrylamidesdisclosed in our copending application filed on even date therewith.

Only the poly(methyl acrylates) are suitable for the reaction withN-methylglucamine and other poly(alkyl acrylates) such as the poly(ethylacrylates), poly(butyl acrylates), and the like cannot be used forreaction with N-methylglucamine, although they may be employed asmodifiers of the methyl acrylate as pointed out heretofore. Furthermore,none of the other modifying monomers set forth previously can be usedfor reaction with the N-methylglucamine. Only the stated poly(methylacrylates) are suitable for reaction with the N-methylglucamine. It isnot entirely certain why the excluded poly(alkyl acrylates) and all ofthe other modifying monomeric units do not react with N-methylglucaminein the same manner as the specific poly( methyl acrylates). It is,however, quite probable that excessive cross-linking and subsequentinsolubilization occurs with the excluded compounds, a result that ishighly undesirable. It is therefore necessary in order to achieve thepurposes of this invention that the copolymeric reactant contain asubstantial portion of methyl acrylate units in order to form thedefined modified water-soluble polyacrylamides.

The integer Y will have a value that will vary according to the amountsof methyl acrylate units that are not converted into a correspondingacrylamide. The actual value of Y is relatively unimportant within thelimits of the molecular ratios of methyl acrylate units and N-methylglucamine previously set forth. To further illustrate therelationship of Y to the entire molecule if two molecular equivalents ofmethyl acrylate are employed for each molecular equivalent ofN-methylglucamine, then the value of Y will be one and if nine molecularequivalents of methyl acrylate are used for each molecular equivalentfor N-methylglucamine, then Y will have a value of eight. Therefore, itis apparent that the actual value of Y will vary according to themolecular equivalents of N-methylglucamine and methyl acrylate unitsemployed and, accordingly, Formulas II and III will so vary.

The integer X will vary generally from about 230 to 4700, but it isimportant that the range of X and Y be such that the product iswater-soluble. The modified poly(methyl acrylate) reactants that areuseful in this invention range in average value molecular weight fromabout 20,000 to somewhat above 400,000.

The compounds of this invention represented by Formula III are preparedby reacting N-methylglucamine and modified poly(methyl acrylate)according to the ratios of Formula II and then hydrolyzing the resultantcompound with an alkaline agent having the formula MOH in which M ispreferably ammonium, sodium, potassium, lithium, and the like. That is,the compounds of Formula II are in ester form, whereas the compounds ofFormula III are hydrolyzed into salt form. What has been said concerningintegers X and Y applies equally to the compounds of Formulas II andIII. Compounds represented by Formulas I, II, and III are analogous andsimilarly useful for the purposes of this invention.

While all of the products of this invention as defined by Formulas I,II, and III are useful for the present purposes there, of course, may besome degrees of differences of properties in addition to themodification of properties previously referred to. For instance,generally, the higher the molecular weight of the modified polymerreactant the more N-methylglucamine is required to conferwater-solubility on the product and conversely. The importantconsideration is that the products should be water-soluble. It is,therefore, clear that another of the objects of this invention is toprepare modified water-soluble polyacrylamides from modifiedwaterinsoluble polymeric compounds and to thereby make products usefulfor many applications not available to the insoluble polymericreactants.

It is necessary to employ in the present reaction an inert organicsolvent, preferably of relatively low volatility. It is preferable thatboth of the reactants be substantially completely soluble or misciblewith the solvent and essentially unreactive with the solvent,particularly the N-methylglucamine. An excess of solvent is frequentlyadvantageous such as from about two to six times the approximate volumeof the reactants. Useful in this respect are dimethylformamide,dimethylsulfoxide, dioxane, and the like.

Temperatures in the range of about to 155 C. are employed with a rangeof -145 C. preferred. There is no appreciable reaction within areasonable time below about 110 C. Substantial reaction rates arenoticed beginning about 115 C. At temperatures appreciably above C.there is the tendency to obtain undesired cross-linked insolubleproducts. Therefore, such higher temperatures should be avoided.Generally, when a temperature in the upper part of the defined range isused a shorter reaction time is necessary and when a temperature in thelower part of the defined range is employed a longer reaction time isrequired. For instance, the reaction is generally complete in aboutthree to five hours when the upper temperature values are used, whereasthe reaction may require from about 20 to 24 hours for completion whenthe lower temperature range is employed varying of course withvariations in the modified copolymeric reactant. However, the reactiontime is not essentially critical but merely reflects upon the yieldsobtained. The important consideration is that the reaction be conductedfor a sufficient length of time to permit the formation of modifiedwater-soluble polymeric products from the corresponding modifiedwater-insoluble polymeric reactants. This means that the reaction shouldnot be conducted for too short or too long a period of time, for in theformer instance, insutficient water solubility will be conferred on theproduct to satisfy the requirements of this invention or, in the latterinstance, the products which have already had sufficient watersolubility conferred upon them may proceed to undesired cross-linkingand concurrent insolubilization. Therefore, the standard to be used isnot that of an absolute time interval but rather that period of timenecessary to confer water solubility on the product and short of thattime when insolubilization might occur. The products of this inventionlie between these two extremes.

Yields in excess of 65 to 72% and above are consistently achieved. Whileall of the mechanics of the present invention are not fully understoodat this time, it is believed that the reaction proceeds so unexpectedlysmoothly because of an autogenous catalytic effect imparted by thepolyhydroxyalkyl group of the N-methylglucamine reactant.

If it is desired to make the products of this invention represented byFormula III, it is only necessary to hydrolyze a compound of Formula IIwith a sufiicient amount of an alkaline agent such as sodium hydroxide,potassium hydroxide, lithium hydroxide, ammonium hydroxide, or 'thelike.

It is possible, if desired, to react a product of Formula II withrelatively low molecular weight amines to produce further aminatedcompounds. Such amines as dimethylamine, dibutylamine,N-methyl-N-propylamine, dimethylaminopropylamine,diethylaminobutylamine, and the like are useful for this purpose.

In order to isolate the product, one may pour the reaction mixture intobenzene or a mixture of benzene and heptane or the like which solvent ormixture of solvents is a non-solvent for the product. The product isthen filtered to separate it from the solvent or mixture of solvents. Itis then desirable to remove any excess of the alkaline neutralizingagent, such as by employing a mixture of cation and anion exchangeresins. The resins may be subsequently separated by filtration and theproduct dried if desired by conventional means, such as under reducedpressure.

The products of this invention range from white or light colored viscousmasses to powders and glass-like resins. The products of this inventionare valuable as aggregants for the conditioning of soil and in thisrespect they have activities superior to those of commerciallyacceptable aggregants. For instance, it is typical for products to causeaggregation to a sufiicient particle size of from 95 to above 98% of allthe particles treated. These products are useful in the paper industryin wet strength applications. The present products are useful in thetextile industry as whiteness retention agents and are markedly superiorto the carboxymethyl cellulose agents particularly in their stabilitytoward microorganisms. They are useful as thickeners in water basepaints and they impart a variety of characteristics to the filmdepending on the amount and nature of the modifying monomeric compoundspresent. Valuable films of significant hardness, toughness, chemicalresistivity, and aqueous passivity may be prepared as desired.

The compounds of this invention and the method for their preparation maybe more fully understood from the following examples which are offeredby Way of illustration and not by way of limitation. Parts by weight areused throughout. Example 1 There are added to a reaction vessel equippedwith a stirrer and thermometer 142 parts of a dimethylformamide 25%solution of a polymer composed of 80% of methyl acrylate, and 20% ofmethyl methacrylate. This solution is diluted with 300 parts ofdimethylformamide and there is then added 97.5 parts ofN-methylglucamine. The reaction mixture is heated to 140 C. under ablanket of nitrogen until the reaction mixture becomes completely watersoluble (about 4% hours). The reaction mixture is then cooled to roomtemperature and poured into 2500 parts of benzene to cause the productto precipitate. The precipitated polymer is cut into small pieces andallowed to soak in benzene overnight. The material is then dried undervacuum. The product is a clear glasslike resin and has a nitrogencontent of 5.38% (5.39% theoretical). The product corresponds to theformula OB-CH1 30 0 CHIJ JONCH J CHAGHOHMC E2011 4.7

In a similar way there are prepared the products of this inventioncorresponding to the following formulae:

on. CH-CH; -CH: l ONCH: milOOCaHul and CH; -OH-OH, CH= LONCHa JOOC5H 1Example 2 Into a reaction vessel there are added 460 parts of adimethylformamide 20% solution of twelve parts of methyl acrylate toeach part of dodecyl methacrylate. A total of 181.2 parts ofN-methylglucamine and parts of dimethylformamide is added. The reactionmixture is heated under a blanket of nitrogen at to C. (three andone-half hours) until the reaction mixture becomes completely soluble incold water. The reaction mixture is then cooled to room temperature andpoured into benzene to precipitate the product. The product is filtered,washed well with heptane, soaked overnight in heptane, and finally driedunder a high vacuum. The product had a nitrogen content of 5.0% (5.03%theoretical) and corresponds to the formula In like manner there areprepared the compounds of this invention corresponding to the followingformulae:

I-CONCH; J LCOOCHj-CH-CIHIJ HzfCHOHMCHgOI-l 10 IH 1 CH-CH.

There is added to a reaction vessel equipped with a stirrer andthermometer 142 parts of a dimethylformarnide 25% solution of acopolymer of 80% methyl acrylate and 20% ethyl methacrylate. Thissolution is diluted with 300 parts of dimethylformamide and there isthen added 58.5 parts of N-methylglucamine. The reaction mixture is thenheated to 140 C. under a blanket of nitrogen until the mixture becomescompletely water soluble (about four and one-half hours). The reactionmixture is then cooled to room temperature and poured into 2500 parts ofbenzene to cause precipitation of the product. The precipitated polymeris cut into small pieces and allowed to soak in benzene overnight. Thematerial is then dried under vacuum. The product is a clear, sticky,soft resin which is soluble in water giving a viscous solution. Thedried polymer has a nitrogen content of 4.6%, indicating that 73.5% ofthe acrylate groups present have reacted with N-methylglucamine. Theproduct has the following structure:

it r

OBI-43H. H-CHr- The above product is dissolved in water to give anaqueous 5% solution and hydrolyzed with an excess of aqueous 40% sodiumhydroxide at room temperature. A commercial grade of cation and anionexchange resins '7 is added to remove the excess sodium hydroxide. Theion exchange resin mixture is separated by filtration and the productused as a water solution. The product may be obtained by drying byconventional means under reduced pressure. The product corresponds tothe following formula:

In a similar way there are prepared the products of this inventioncorresponding to the following formulae:

1. A method for the preparation of a modified watersolublepolyacrylamide which comprises reacting a poly (methylacrylate), thathas been modified by any monomeric unit that forms copolymers withmethyl acrylate, with N-methylglucamine at a reaction temperature in therange of 115 to 155 C. in the presence of an inert volatile organicsolvent and concluding the reaction while a water-soluble product isobtained.

2. A method for the preparation of a modified watersolublepolyacrylamide which comprises reacting a poly (methylacrylate), thathas been modified by any monomeric unit that forms copolymers withmethyl acrylate, with N-methylglucamine in such molecular proportionsthat about 0.1 to 1.1 equivalents of N-methylglucamine are present foreach equivalent of methyl acrylate at a reaction temperature in therange of 115 to 155 C. in the presence of an inert volatile organicsolvent and concluding the reaction while a water-soluble product isobtained.

3. A method for the preparation of a modified watersolublepolyacrylamide which comprises reacting a poly (methyl acrylate), thathas been modified by a member from the class consisting of (1) alkylacrylates and (2) alkyl methacrylatcs, with N-methylglucamine in suchmolecular proportions that about 0.1 to 1.1 equivalents ofN-methylglucamine are present for each equivalent of methyl acrylate ata reaction temperature in the range of 120 to 145 C. in the presence ofan inert volatile organic solvent and concluding the reaction while awatersoluble product is obtained, wherein said (1) alkyl contains fromtwo to eighteen carbon atoms and said (2) alkyl contains one to eighteencarbon atoms.

4. A method for the preparation of a modified watersolublepolyacrylamide which comprises reacting a copolymer of methyl acrylateand an alkyl methacrylate with N-methylglucamine at a reactiontemperature in the range of 115 to 155 C. in the presence of an inertvolatile organic solvent and concluding the reaction while awater-soluble product is obtained, wherein said alkyl group containsfrom one to eighteen carbon atoms.

5. A method for the preparation of a modified watersolublepolyacrylamide which comprises reacting a copolymer of methyl acrylateand an alkyl acrylate with N-methylglucarnine at a reaction temperaturein the range of 115 to 155 C. in the presence of an inert vol t leorganic solvent and concluding the reaction while a water-solubleproduct is obtained, wherein said alkyl group contains from two toeighteen carbon atoms;

6. A method for the preparation of a modified watersolublepolyacrylamide which comprises reacting a copolymer of methyl acrylateand an alkyl methacrylate with N-methylglucamine at a reactiontemperature in the range of to 155 C. in the presence of an inertvolatile organic solvent and concluding the reaction while awater-soluble product is obtained and hydrolyzing the water-solubleproduct with an alkaline agent, wherein said alkyl group contains fromone to eighteen carbon atoms.

7. A method for the preparation of a modified watersolublepolyacrylamide which comprises reacting a copolymer of methyl acrylateand an alkyl acrylate with N-methylglucamine at a reaction temperaturein the range of 115 to 155 C. in the presence of an inert volatileorganic solvent and concluding the reaction while a watersoluble productis obtained and hydrolyzing the watersoluble product with an alkalineagent, wherein said alkyl group contains from two to eighteen carbonatoms.

8. A method for the preparation of a modified watersolublepolyacrylamide which comprises reacting a copolymer of methyl acrylateand an alkyl methacrylate having a molecular weight of 20,000 to about400,000 with N-methylglucamine at a reaction temperature in the range ofto C. in the presence of an inert volatile organic solvent andconcluding the reaction while a water-soluble product is obtained andhydrolyzing the water-soluble product with an alkaline agent, whereinsaid alkyl group contains from one to eighteen carbon atoms.

9. A method for the preparation of a modified watersolublepolyacrylamide which comprises reacting a copolymer of methyl acrylateand an alkyl acrylate having a molecular weight of 20,000 to about400,000 with N- methylglucamine at a reaction temperature in the rangeof 120 to 145 C. in the presence of an inert volatile organic solventand concluding the reaction while a water-soluble product is obtained,wherein said alkyl group contains from two to eighteen carbon atoms.

10. A modified water-soluble polyacrylamide of poly- (methyl acrylate),that has been modified by any monomeric unit that forms copolymers withmethyl acrylate and N-methylglucamine.

11. A modified water-soluble polyacrylamide of poly- (methyl acrylate),that has been modified by any monomeric unit that forms copolymers withmethyl acrylate and N-methylglucamine, in which there are from 0.1 to1.1 equivalents of N-methylglucamine for each equivalent of methylacrylate.

12. A modified water-soluble polyacrylamide of poly- (methyl acrylate),that has been modified by any monomeric unit that forms copolymers withmethyl acrylate and N-methylglucamine, in which there are from 0.1 to1.1 equivalents of N-methylglucamine for each equivalent of methylacrylate, said modified poly(methyl acrylate) having an average valuemolecular weight of about 20,000 to about 400,000.

13. A modified water-soluble polyacrylamide of poly- (methyl acrylate),that has been modified by a member from the group consisting of (1)alkyl methacrylates in which said 1) alkyl group contains from one toeighteen carbon atoms and 2) alkyl acrylates in which said (2) alkylgroup contains from two to eighteen carbon atoms, and N-methylglucamine.

14. A modified water-soluble polyacrylamide of poly- (methyl acrylate),that has been modified by a member from the group consisting of (1)alkyl methacrylates in which said 1) alkyl group contains from one toeighteen carbon atoms and 2) alkyl acrylates in which said (2;) alkylgroup contains from two to eighteen carbon atoms, and N-methylglucamine,in which there are from 0.1 to 1.1 equivalents of N-methylglucamine foreach equivalent of methyl acrylate.

15. A modified water-soluble polyacrylamide of poly- (methyl acrylate),that has been modified by a member from the group consisting of (1)alkyl methacrylates in which said 1) alkyl group contains from one toeighteen carbon atoms and 2) alkyl acrylates in which said (2) alkylgroup contains from two to eighteen carbon atoms and N-methylglucamine,in which there are from 0.1 to 1.1 equivalents of N-methylglucamine foreach equivalent of methyl acrylate, said modified poly(methyl acrylate)having an average value molecular weight of about 20,000 to about400,000.

16. A modified water-soluble polyacrylamide of poly- (methyl acrylate),that has been modified by an alkyl 10 methacrylate in which said alkylportion contains from 1 to 18 carbon atoms, and N-methylglucamine.

17. A modified water-soluble polyacrylamine of poly- (methyl acrylate),that has been modified by an alkyl acrylate in which said alkyl portioncontains from 2 to 18 carbon atoms, and N-methylglucamine.

References Cited in the file of this patent UNITED STATES PATENTS2,744,885 De Benneville et al. May 8, 1956

1. A METHOD FOR THE PREPARATION OF A MODIFIED WATERSOLUBLEPOLYACRYLAMIDE WHICH COMPRISES REACTING A POLY (METHYLACRYLATE), THATHAS BEEN MODIFIED BY ANY MONOMERIC UNIT THAT FORMS COPOLYMERS WITHMETHYL ACRYLATE, WITH N-METHYLGLUCAMINE AT A REACTION TEMPERATURE IN THERANGE OF 115* TO 155*C. IN THE PRESENCE OF AN INERT VOLATILE ORGANICSOLVENT AND CONCLUDING THE REACTION WHILE A WATER-SOLUBLE PRODUCT ISOBTAINED.